1. Field of the Invention
The present invention relates to a liquid crystal display manufactured by a one drop fill method and a method of manufacturing the liquid crystal display.
2. Description of the Related Art
A typical liquid crystal display includes a liquid crystal layer between a drive substrate and an opposed substrate. A TFT (Thin Film Transistor) device layer, a pixel electrode layer, a planarization layer and an alignment film are arranged on the drive substrate (a TFT substrate). On the other hand, a BM (Black Matrix) layer (a frame region), a CF (Color Filter) layer, a common electrode and an alignment film are arranged on the opposed substrate. Moreover, a sealing layer is arranged between the drive substrate and the opposed substrate so as to adhere the substrates together and to prevent liquid crystal leakage.
As a method of forming a liquid crystal layer between a pixel substrate and an opposed substrate in a liquid crystal display with such a configuration, a vacuum injection method in which the pixel substrate and the opposed substrate are bonded together, and then a liquid crystal is injected is used. However, the method needs a long time to inject the liquid crystal, so there is an issue that when the areas of the substrates increase, productivity becomes poor.
To solve the issue, a method called an ODF (One Drop Fill) method has been developed. For example, as described in Japanese Unexamined Patent Application Publication No. 10-186384, in the method, a liquid crystal material is dropped on one of two substrates before bonding the two substrates together for sealing. In the ODF method, as a material (a sealant) forming a sealing layer, a UV (ultraviolet)-curable sealant or a combination type sealant is used. Moreover, Japanese Unexamined Patent Application Publication No. 10-186384 also discloses that the liquid crystal is dropped, and two substrates are bonded together, and then the liquid crystal is spread by a pressure roller so as to easily seal the liquid crystal between the substrates for a short time. Thereby, mass production of the liquid crystal displays is allowed, and in the case of small- to medium-size liquid crystal displays, an injection opening for sealing the liquid crystal is not necessary, so a substrate thickness for sealing the injection opening is not necessary, thereby a reduction in profiles of the liquid crystal displays is allowed.